Lock assembly with a curved keyway and a flexible key for actuation thereof

Abstract

A lock assembly includes a lock and a flexible key. The lock includes a lock and an elongated plug unit having a longitudinal curved keyway that is accessible by the key. The keyway has several turns and several branch slots, each of which extends from one of the turns of the curved keyway in a direction different from that of a portion of the curved keyway succeeding the turn so as to mislead an undesirable flexible stick into the slot.

What is claimed is: 
     
       1. A lock assembly including a lock and a flexible key for actuating said lock, said lock including an elongated plug unit that is mounted rotatably in said lock and that has a longitudinal curved keyway accessible by said key, said keyway having several turns, said plug unit further having several branch slots each of which extends from a respective one of the turns of said curved keyway in a direction different from that of a portion of said curved keyway succeeding the respective one of the turns so as to mislead an undesirable flexible stick into said slot, thereby preventing said lock from being picked by the flexible stick, said plug unit including a keyway member having said curved keyway and said slots formed therethrough, and two elongated lock pieces which are shaped in the form of two elongated cylinder halves and which cooperatively confine said keyway member therebetween, said keyway member having two planar opposite side surfaces, each of said cylinder halves having an abutting surface which abuts against one of said side surfaces of said keyway member and which is formed with a plurality of lengthwise extending grooves therein in communication with said keyway and said slots, said keyway member including two adjacent stacks of elongated metal sheets between which said keyway and said slots are defined.   
     
     
       2. The lock assembly as defined in claim 1, wherein each of said sheets has serrated top and bottom surfaces each of which is formed with a plurality of lengthwise extending grooves, one of said sheets in one of the stacks having an inner side portion which extends into said keyway and which is spaced apart from the other one of said stacks of said sheets, whereby, when inserted into said keyway of said plug unit, the picking stick can be misled into one of said lengthwise extending grooves of said inner side portions of said sheets so as to prevent said lock from being picked by the stick. 
     
     
       3. The lock assembly as defined in claim 1, wherein each of said sheets has serrated top and bottom surfaces each of which is formed with a plurality of lengthwise extending grooves, one of said sheets in one of the stacks having a serrated inner side edge which extends into said keyway and which is spaced apart from the other one of the stacks of said sheets, said serrated inner side edge having a row of notches, whereby, when inserted into said keyway of said plug unit, the picking stick can be misled into one of said notches so as to prevent said lock from being picked by said stick. 
     
     
       4. A lock assembly including a lock and a flexible key for actuating said lock, said lock including an elongated plug unit that is mounted rotatably in said lock and that has a longitudinal curved keyway accessible by said key, said keyway having several turns, said plug unit further having several branch slots each of which extends from a respective one of the turns of said curved keyway in a direction different from that of a portion of said curved keyway succeeding the respective one of the turns so as to mislead an undesirable flexible stick into said slot, thereby preventing said lock from being picked by the flexible stick, wherein said flexible key includes a chain of successively hinged knuckles having parallel rotating axes, each of said knuckles having a blind pivot hole unit formed therein with a closed inner end section and an open outer end section, and an open-ended pivot hole unit formed through said knuckle, said chain including a plurality of tubular pivots, each of which interconnects an adjacent pair of said knuckles and each of which has an enlarged inner end portion that is received within said inner end section of said blind pivot hole unit of one of said knuckles in such a manner that said enlarged inner end portion has a section which is press-fitted within said inner end section of said blind pivot hole unit of the one of said knuckles, an enlarged outer end portion that is press-fitted within said outer end section of said blind pivot hole unit of said one of said knuckles and having a greatest diameter slightly larger than that of said enlarged inner end portion of said pivot, and an intermediate portion that interconnects said enlarged inner and outer end portions and that extends through said open-ended pivot hole unit of another one of said knuckles, said intermediate portion of each of said pivots having a diameter smaller than that of said enlarged inner end portions of said pivots and than that of said open-ended pivot hole units of said knuckles to assist in relative rotation of any adjacent pair of knuckles. 
     
     
       5. The lock assembly as defined in claim 4, wherein each of said pivots is made of a spring steel and is shaped in the form of a circular tube which has an axially extending slot extending over a total length thereof so as to assist in insertion of said pivot into one of said blind pivot hole units of said knuckles. 
     
     
       6. The lock assembly as claimed in claim 4, wherein said inner and outer end sections of each of said blind pivot hole units of said knuckles have different diameters in such a manner that the diameter of said inner end section is smaller than that of said outer end section, each of said enlarged inner and outer end portions of said pivots including a plurality of truncated conical sections, each of which has a smallest diameter at an inner end thereof, and a greatest diameter at an outer end thereof, said enlarged inner and outer end portions of said pivots respectively abutting against walls of said knuckles which define said blind pivot hole units so as to facilitate insertion of said pivots into said blind pivot hole units and so as to prevent disengagement of said pivots from said blind pivot hole units. 
     
     
       7. A lock assembly including a lock and a flexible key for actuating the lock, the lock including an elongated plug unit that is mounted rotatably in the lock and that has a longitudinal curved keyway accessible by the key, the keyway having several turns, the plug unit further including a keyway member having the curved keyway, and two elongated lock pieces which are shaped respectively in the form of two elongated cylinder halves and which cooperate to confine the keyway member therebetween, said keyway member further having several branch slots formed therethrough in communication with said keyway, said keyway member being formed by two adjacent stacks of elongated metal sheets which define the keyway and the slots therebetween and which have two planar opposite side faces, each of the cylinder halves having an abutting surface which abuts against one of the side surfaces of the keyway member. 
     
     
       8. The lock assembly as defined in claim 7, wherein each of said branch slots extends from a respective one of the turns of the curved keyway in a direction different from that of a portion of the curved keyway succeeding the respective one of the turns so as to mislead an undesirable flexible stick into the slot, thereby preventing the lock from being picked by the flexible stick. 
     
     
       9. The lock assembly as defined in claim 7, wherein the abutting surface of the respective one of said cylinder halves is formed with a plurality of lengthwise extending grooves therein in communication with the keyway and the slots.